1 Suggested Answer

Hi,
A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).click here to download the app (for users in the US for now) and get all the help you need. Good luck!

Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.

Hi, you will want to fix both codes. The reason is that when the computer is not getting data from the knock sensor it defaults to a safe ignition timing that reduces performance. The misfire requires troubleshooting. First check the plug and wire. If that's good, run a compression test. If that's good, check the injector pulse (use a voltmeter set to AC, and compare voltage to other injectors--with engine running). If the pulse is good, check to see if the injector is clicking. If it isn't clicking, you know it's bad. It might also be clogged, but you have to pull the fuel rail to see if it's clogged.
Please see my tip at http://www.fixya.com/cars/r6715318-causes_gasoline_engine_misfires . These are genericinstructions. If you get stuck or need specific instructions for your car, please get back to me with model, year and engine info.

I would think that if the problem was fuel presssure, it would affect all cyliners, not just the one. I would look for a fouled spark plug or a bad plug wire. I had a similar problem with one cylinder misfiring, throwing multiple trouble codes. Turned out to be the distributor cap and rotor.

codes 03-40 are misfires on cylinders 3 & 4 and 325 is ur knock sensor if u had bad gas/water in tank or need tune up and those 2 cylinders misfired could set off code for knock sensor or visa versa as to abs light sheck sensor wires for connection and or damage none observed have rescanned and find out if sensor or unit if sensor scan code will tell u which one ur directional usually blinks faster on the side with the bulb out

If the knocking did not go away with the higher octane fuel then you may have other problems. A dirty fuel injector oor a misfiring spark plug can also cause knocking in a modern car. A faulty sensor may also be causing the wrong fuel / air mixture in the cylinder... check out the cheapest fixes first.